Refuels are suitable for everyday use

Karlsruher Institut für Technologie (KIT)

Synthetic fuels produced from renewable sources, so-called refuels, are deemed potential game changers in fighting climate change. Refuels promise to reduce CO2 emissions by up to 90% compared to conventional fuels and they allow for the continued use of existing vehicle fleets with combustion engines and of the refueling infrastructure, from fuel production to transport to sales. Researchers of Karlsruhe Institute of Technology (KIT) carried out extensive fleet tests in a large-scale project with industry partners and proved that refuels can be used in all vehicles and produced in large quantities in the foreseeable future. The results of the research project “reFuels — Rethinking Fuels” were presented on Monday, September 19, in Karlsruhe.

“Use of climate-neutral fuels makes sense especially when battery-electrical solutions do not yet represent real alternatives. Hence, I am very happy that KIT has now succeeded in proving that refuels are both climate-friendly and economically efficient for certain applications,” says Berthold Frieß, Head of Department at the Baden-Württemberg Ministry of Transport, at the presentation of results of “reFuels — Rethinking Fuels,” the first refuels project of the Strategy Dialog for the Automotive Sector in Baden-Württemberg. “The project also shows that the efforts undertaken by the State and the project partners to support renewable fuels were worthwhile. Baden-Württemberg remains a pioneer in the transformation of the mobility sector.” Under the Strategy Dialog Program, the State Ministry of Transport supported the project with EUR 5 million. Another 15 million euros were provided by industry.

Continued Environmentally Friendly Use of Existing Vehicle Fleets

“In the foreseeable future, we will not be able to do without liquid fuels, especially in heavy-duty traffic, shipping, aviation, as well as in the existing car fleet,” says Professor Thomas Hirth, KIT Vice-President for Transfer and International Affairs. “In the “reFuels — Rethinking Fuels” project, we have now demonstrated that refuels work in both old and new cars as well as in commercial vehicles and locomotives,” Hirth adds. “To sum up, refuels are fully and entirely suited for everyday use!”

CO2 Reduction by up to 90 Percent

“We produced tons of refuels that meet standards existing for Otto and diesel fuels and do not cause any car decline or wear when widely used in various types of engines,” explains Dr. Olaf Toedter from KIT’s Institute of Internal Combustion Engines. KIT researchers produced and tested both petrol and diesel fuel. Depending on the mixing ratio of synthesized and fossil fuels, the initial materials used, and the energies, they reached a CO2 reduction by 22 to 90 percent.

Industrial Production Facility Planned in Karlsruhe

As a next step, the project partners plan to build an industrial facility to produce refuels on the premises of the MiRO refinery in Karlsruhe. “In the long run, we will replace fossil resources by renewable energy carriers,” says Dr. Andreas Krobjilowski, Technical Director of MiRO. “Many technologies and processes required for this purpose are already available in Germany. MiRO has the know-how and expertise to build and operate such new and innovative facilities.” However, affordable quantities of green hydrogen are not yet sufficient to start greenhouse gas-neutral production. For this reason, reFuel precursors, such as synthesized Fischer-Tropsch oil or methanol, are planned to be produced in countries having more wind or solar power than Germany, such as Chile or South Spain. The refuels proper — petrol, diesel, or kerosene — would then be produced by domestic refineries like MiRO. “For the urgently needed market launch, however, we need clarity and long-term security. It must be ensured that renewable, power-based fuels can be counted for our greenhouse gas reduction rate,” Krobjilowski says.

Pure Refuels Are Within Reach

Researchers are also working on increasing the share of refuels in the fuel mixtures while complying with existing fuel standards. “In the end, pure reFuels will result,” Toedter says. Ongoing tests are promising. However, clear regulations are still lacking. At the moment, the share of admixed reFuels must not exceed 26 percent in case of Diesel in Germany.

The Project “reFuels — Rethinking Fuels”

Within the project launched in 2018, researchers studied the production and use of renewable fuels in a holistic approach. Such fuels may be used in existing combustion engines of airplanes, commercial and railway vehicles, as well as cars. Within the Strategy Dialog for the Automotive Sector in Baden-Württemberg, six institutes of KIT and several partners from energy, mineral oil, automotive, and supply industries worked on the production and introduction of reFuels. Two pilot plants and other technical facilities of KIT supplied regenerative fuels for further processing, characterization, and tests in existing combustion engines and vehicles. This way, synthesis processes for refuels and their use were optimized. Apart from CO2 emissions, also raw emissions were reduced. (mex)

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